Modified approach for apoptosis detection reveals changes in apoptotic processes in the seminoma-associated tissue

Apoptosis morphology (DNA condensation) and internucleosomal DNA cleavage (TdT assay) were measured simultaneously on double fluorescence labeled testis tumor sections, employing conventional immunofluorescence microscopy. Six different apoptosis indices (Al) were determined based either solely on morphological or biochemical criteria, or on a combination of both processes. Measurements were performed in metastasized and non-metastasized seminoma, and in histological regions located distantly and associated with the tumor. Preliminary results on 19 histologies revealed that up to 66% of apoptotic cells were not detected, depending on the method used for apoptosis detection. Besides, no changes of solely morphologically defined Al was found in the different histological regions. By contrast, significant changes (p < 0.0004) in the different histological regions were detected when measuring Als, e.g., defined by DNA fragmentation occurring without DNA condensation in apoptotic cells. Those changes were not detected in metastasized seminoma. These data, for the first time allow a comparison of two widely used approaches for apoptosis detection. Furthermore, the results revealed differences in apoptotic processes in tissue associated with non-metastasized seminoma detectable by a modified evaluated TdT assay but not by morphological changes, although this TdT method fails to show the total amount fo apoptotic cells.